DP Chemistry (last assessment 2024)

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Question 22M.2.hl.TZ1.6a(ii)

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Date May 2022 Marks available [Maximum mark: 2] Reference code 22M.2.hl.TZ1.6a(ii)
Level hl Paper 2 Time zone TZ1
Command term Deduce, Show Question number a(ii) Adapted from N/A
a(ii).
[Maximum mark: 2]
22M.2.hl.TZ1.6a(ii)

Nitric acid is usually produced by the oxidation of ammonia.

(a(ii))

Deduce a Lewis (electron dot) structure of the nitric acid molecule, HNO3, that obeys the octet rule, showing any non-zero formal charges on the atoms.

[2]

Markscheme

bonds and non-bonding pairs correct ✔

formal charges correct ✔

 

Accept dots, crosses or lines to represent electron pairs.

Do not accept resonance structures with delocalised bonds/electrons.

Accept + and – sign respectively.

Do not accept a bond between nitrogen and hydrogen.

For an incorrect Lewis structure, allow ECF for non-zero formal charges.

Examiners report

Drawing the Lewis structure of HNO3 was performed extremely poorly with structures that included H bonded to N, no double bond or a combination of single, double and even a triple bond or incorrect structures with dotted lines to reflect resonance. Many did not calculate non-zero formal charges.

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